crossmember welds

[lm48]

After removing the engine and transmission from an 80 spider and a very deep cleaning of the engine bay I notice that the cross member has multiple welds at the connection with the body. I do not really know how the car drives because I only drove the car ones around the block. I do have a 79 parts car. Do I should replace the cross member from 80 with the one from 79, or I should not worry? Thank you

Liviu



[img][IMG=http://img20.imageshack.us/img20/2003/crossmember.jpg][/img]

Uploaded with ImageShack.us[/img]

[kmead]

Not how it should be. I suspect the bolts that go up into that frame member have pulled our or at the least were spinning and thus the owner instead of fixing the problem properly had it welded up.

There are a few threads about how to fix this, it is a bit involved but it is the right way,

[azygoustoyou]

I agree. I bet those bolts are spinning and the only way to hold it on was to weld it. To fix it right, you'll have to cut the welds and find the real issue. If the bolts are spinning, you'll have to open up the frame and either replace them or do what I did and fix it so the bolt goes all the way through the frame of the car and cross member to hold it on. Since you have the engine and tranny out. You'll have some room. It's still no fun welding upside down. Are you doing a full restoration? The best and easiest way to fix it is when it's upside down.

[lm48]

I am not going to do a frame of restoration; at least that was not the original intention. I already spend 6 weekends on a 79 with to much rust before finding this 80. The welds are very bad done. I will love to have a rotisserie rack but I do not have the space. I leave in a gated community with no way to do any work in the driveway. So, I do all the work with the garage door closed and sometime the chemical fumes are too strong. I will do a cross member transplant from 79 to 80. When I looked at your restoration picture I realized that is something wrong with the way my cross member was secured. You did an amazing job on your restoration.

[lm48]

I got out the cross member from a 79, sandblasted and painted black. Looks like new. Looking closer at the 79 and 80 I notice that 80 left side frame is different then the right side. On the 79 left side of the car is identical with right side. On the 80 the right side is reset back by almost ¼” comparing with driver side. This will make the cross member from 79 not to be a direct fit to 80. The big question is to shim vertical the cross member on the right side or shave the bottom right outside of the cross member. I need to maintain the same engine position in relation to the frame.
As you can see the cross member is not in the final place.
Thank you for your help



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[racydave]

That is alot of difference to compensate for. Assuming the crossmembers are the same. I would like to see it on a frame rack with a good frame tech to set it correctly. Other than that it would need to be set on a very flat floor with the jack points being a consistant height. Then measurements from the front to rear, and cross measurements. It needs to be square, and uniform in height also. You may need to decide which boltholes are incorrect by measurments, as the other side could be the problem??? Fortunatly, I have a good friend that is a good frame man! And I have watched him work frames too. It might be worth the investment to find a good frame man with a laser rack??? Good luck!

[lm48]

Each side of the crossmember is attached to the unibody by 2 vertical bolts and one horizontal on each side. I went to look at the unibody of the 79 (the donor). The distance between the left to right by the crossmember position is 23”, under need by the welding flange is 26.5” with a 1.750 shoulder on either sides, left or right. This shoulder is where the 2 vertical bolts are located. So perfect symmetrical. On other side, the 80 uniframe has an asymmetrical setup. The driver side has the sane 1.750 shoulders but the passenger side is only 1.5” at the crossmember location. This is where the picture shows a set back. Front to back the location is identical on both cars. On 80 the left to right at the crossmember is 23.250”. Also the horizontal dimension from the 2 vertical bolts from left to the 2 vertical bolts on the right is the same on 79 or 80. In order for me to install the 79 crossmember to the 80 I will need ¼” shim around the horizontal bolt on passenger side. I will use a custom fabricated shim to fill in all the space. I will post picture as I am fabricating and completing the installation.

[lm48]

here are the results os a Sunday work



[imghttp://img841.imageshack.us/img841/8194/img00398201109251527.jpg][/img]

[azruss]

you have opened Pandora's box, my friend. The camber is determined by how this piece locates with the unibody. sounds like the right front corner was whacked in a wreck and someone did a bad rebuild. you need to find a flat surface to set the car. mount the crossmember to the drivers side frame and hold the other side up with a clamp. now measure how close the lower a-frame bolt plate and the upper a-frame bolt hole is to vertical. Both sides need to be the same within reason. If the cross member plate sticks out farther than the upper bolt, you will never be able to set the camber. Also need to measure from the back wheels to the front to make sure you have the same wheel base on each side. hard to do this by yourself. As suggested find a good frame shop and see what they can do. Good luck

[htchevyii]

I think some replacement cross members come with shims so they fit more applications. Here's Kelly Dicker of Wine Country Motors' picture of a new one that he had some reinforcement done to. Note the attached triangular shims.
http://www.sonic.net/~kd/personal/124%2 ... C-234F.JPG
Also found a similar pic @ Fiat Plus. It says 79 to 84 are the same. http://www.fiatplus.com/front-suspensio ... 86340.html

[lm48]

You are right htchevyii, the triangle shim is what I need. On the right side only. Thank you for sending me the links.

I made the decision to weld the vertical sleeve inside of the frame in order to use cylinder head bolts and it will work just fine. I looked closely at the 79 frame and 80 and there are different. so the crossmember is different. Both they have the frame 23”apart but on 80 at the crossmember position the frame is set back by 7/32”. In order to use the 79 crossmember on 80 frame I will need a triangle shim as somebody suggested. All the holes matched perfect.

[lm48]

I never posted a picture of finish job, here it is. Some of the old pictures where deceiving showing a misalignment between holes but there was no misalignment, was a missing shim which was welded really bad to the original cross member and because I had to cut 1” at the time I did not see the shim. Job done

[spidernut]

I ran into the same issue on my 79. I replaced the cross member with an 81 cross member and it had the extra plate welded to it. The 79/80 carb'd Spiders did not due to the lack of the notch in the frame rail. I can't figure out why they notched the frame rail on the EFI Spiders then added in the spacer...makes no sense to me at all.

[124JOE]

i thought about it for awhile and came up with this

they probably need more room for quicker install
then throw in the shim"less time than banging it in"

[lm48]

Just another set back. Since I started the restoration 7 months ago I feel that for every step toward completion I am making 2 back words. I replaced a wining transmission and a bad 4th gear with a quiet transmission but popping out from second gear. I had all the assurance that the transmission is perfect. Finally I had a chance to drive the car for the fist time. Smooth ride, but the break buster starts leaking air. So I have to rebuild the buster and get some transmission part